Peat

Owing to the high groundwater level and specific chemical conditions, peat begins to form on bogs. This is a layer of dead marsh plants, which due to the lack of oxygen do not rot but accumulate there, making the layer of peat gradually thicker. Until the plants grown on peat retain their contact with groundwater and access to mineral substances, we can speak of fens. In favourable conditions, however, the peat layer can become so thick that its upper part can no longer be supplied with groundwater. A raised bog is formed. The only water source for the raised bog plants is precipitation, the quantity of nutrients is insignificant. In this extreme but modest environment can survive only plants that are specifically adapted to these conditions. The most important builders of raised bogs are peat mosses, which can rapidly absorb exceptional quantities of rainwater and retain it through dry spells.